Since apoptosis of endothelial cells (ECs) plays an important role in the pathogenesis of atherosclerosis, we investigated the effect of cyclic stretch on EC apoptosis. Application of moderate, physiologic levels of cyclic stretch (6–10% at 1 Hz) inhibited EC apoptosis. This anti-apoptotic effect was dependent on the activation of phosphatidylinositol 3-kinase and associated with the activation of Akt and the phosphorylation of Bad. Interestingly, a higher potentially pathologic level of cyclic stretch (20% at 1 Hz) stimulated EC apoptosis. The ability of physiologic cyclic stretch to inhibit EC apoptosis may provide a previously unrecognized mechanism by which hemodynamic forces exert an anti-atherogenic effect.
